Re: How to substitute in a string for the first n matches?

[Denis Shirokov]

      if you want to process large data the you must have to use a
pointer - not an string as the source but the pointer:


      func  repn( ptr, regexp, n, rep ,currpos,A ) {

            currpos = 1

            "" in A

            while ( n-- > 0 && match( substr( _SOURCE[ ptr ], currpos
), regexp ) ) {

                  A[ length( A ) ] = substr( _SOURCE[ ptr ], currpos,
RSTART - 1 ) rep

                  currpos += RSTART + RLENGTH - 1 }

            return _reta( A ) }


        the source should be stored in _SOURCE[ ptr ] before repn() will be
calling. the ptr may be an any
        string.

        but for gawk the most effective way will be:


      func  repn( t, regexp, n, rep ,T,D ) {

            if ( patsplit( t, T, regexp, D ) ) {

                  for ( t = 1; t <= n; t++ )

                        T[ t ] = rep

                  return _retab( T, D ) }

            return t }



      you can find implementation of the function _reta() (and not the
only) in include file
      _arr.mod. the file is available to download from
https://github.com/digics/gawklib.
      just include its at any point of your gawk project. the library
isn't requiring any
      initializations. small documentation file for this library is
also present in _arr.rtf.
      check out the performance part of the documentation.

      Good Luck!

kind Regards
Denis